Document: KAR-3-59-83

Carbon budgets and net ecosystem productivity of two contrasting boreal black spruce ecosystems in central Saskatchewan.

BISBEE, K.*, T.GOWER and J.NORMAN

University of Wisconsin, Madison, WI 53706 ¹

Abstract:
Boreal forests are of great interest because they store a large amount of carbon in the soil and because of their pivotal role in the global carbon cycle. The objective of this study was to compare the carbon budget of two similar-aged boreal black spruce ecosystems with contrasting structure: Closed-canopy black spruce with a feathermoss ground cover and open-canopy black spruce with sphagnum ground cover. Soil carbon content was over two-fold greater for the open- versus closed-canopy black spruce ecosystems, which suggests that annual carbon accumulation is over 100% greater. Aboveground net primary production (ANPP) of the overstory was two-fold greater for the closed- than open-canopy black spruce stands, but the ground cover NPP was over three-fold greater for the open- than closed-canopy black spruce stands, resulting in a similar aboveground NPP. Belowground NPP was roughly proportional to ANPP. Because of lower decomposition rates, the net ecosystem production of the black spruce - sphagnum ecosystem was greater (more of a sink) than that of the black spruce - feathermoss ecosystem. The results from this study illustrate the profound influence small differences in edaphic conditions can have on ecosystem carbon dynamics, and the need to better characterize the spatial heterogeneity of canopy structure and ground cover composition on ecosystem carbon dynamics.

Keywords: net ecosystem production, carbon budget, boreal black spruce forest

This abstract is being presented at: 4:00 PM in session:
Oral Session #52: Carbon Storage in Ecosystems.